Point-Counterpoint: Reflex Cultures Reduce Laboratory Workload and Improve Antimicrobial Stewardship in Patients Suspected of Having Urinary Tract Infections

Impact of Urine Culture Reflex Policy Implementation in a Large County Hospital Inpatient Rehabilitation Unit-A Pilot Study

OBJECTIVE

To promote antimicrobial stewardship, many institutions have implemented a policy of reflexing to a urine culture based on a positive urinalysis result. The rehabilitation patient population, including individuals with brain and spinal cord injuries, may have atypical presentations of urinary tract infections. The study objective is to determine the effects of implementing a urine culture reflex policy in this specific patient population.

DESIGN

In an inpatient rehabilitation unit, 348 urinalyses were analyzed from August 2019 to June 2021. Urinalysis with greater than or equal to 10 white blood cells per high power field was automatically reflexed to a urine culture in this prospective study. Primary outcome was return to acute care related to urinary tract infection. Secondary outcomes included adherence to reflex protocol, antibiotic utilization and appropriateness, adverse outcomes related to antibiotic use, and reduction in urine cultures processed and the associated reduction in healthcare costs.

RESULTS

There was no statistically significant difference before and after intervention related to the primary outcome. Urine cultures processed were reduced by 58% after intervention.

CONCLUSIONS

Urine culture reflex policy is likely an effective intervention to reduce the frequency of urine cultures without significantly affecting the need to transfer patients from inpatient rehabilitation back to the acute care setting.

Alternative Strategies to Provide Actionable Results When a Supply of Urinalysis Strips Is Unavailable

CONTEXT.—

Urinalysis instrument-specific dip strips offer physicians qualitative results for actionable analytes (protein, glucose, leukocyte esterase, nitrates, hemoglobin, and ketones).

OBJECTIVE.—

To explain a strategy implemented to support clinical decision-making by providing urine quantification of protein, glucose, white blood cells (WBCs), and red blood cells because of urine strip shortages.

DESIGN.—

During shortages, we implemented an automated algorithm that triggered sending urine samples to the automation line for quantification of protein and glucose and ensured that urine microscopy was performed to obtain WBC and red blood cell counts. The algorithm printed 2 labels so nursing staff would collect 2 specimens. We monitored the turnaround time from the specimen being received in the laboratory to result verification, ensured that the culture reflex order was triggered, and tracked complaints by physicians regarding not having usual urinalysis results. Prior to implementation, correlation between sample types for protein and glucose measurement was found acceptable.

RESULTS.—

The algorithm was put in place twice during 2022. The turnaround time of urine microscopic study was identical to that obtained when the urinalysis was done with the strips; however, the quantification of glucose and protein took approximately 30 minutes more. Urine reflex cultures were triggered correctly with the algorithm, as they were derived entirely from a WBC count higher than 10 per high-power field. During the shortage period we had only 1 complaint, by a physician wanting to have results of nitrates.

CONCLUSIONS.—

During urine strip shortages, we successfully implemented a diversion algorithm that provided actionable urinalysis analytes in a timely manner with minimal provider complaints.

Positive predictive value of urine analysis with reflex criteria at a large community hospital

INTRODUCTION AND HYPOTHESIS

Urine analysis with reflex to culture (URTC) is employed as a diagnostic aid for urinary tract infections (UTIs). Criteria utilized to determine whether a urine analysis (UA) will reflex varies owing to a lack of evidence-based guidance. Positive predictive value (PPV) of URTC varies across studies. The URTC criteria in this study included moderate or more white blood cells (> 5 high-power field [HPF]), few or more bacteria (> 1 HPF), and few or no epithelial cells (< 3 HPF). The purpose of this study was to determine the extent to which URTC predicts culture positivity.

METHODS

This study was a single-center, retrospective evaluation at a large community hospital. A report of URTC ordered in adults in October 2020 was generated from the hospital's electronic database. The primary outcome was to determine the PPV of URTC criteria. The secondary outcome was to examine the differences in microscopic UA results between culture-positive and culture-negative urine. A total of 350 patients were included for analysis. The data was analyzed through descriptive statistics, Mann-Whitney U test, and multivariate logistic regression.

RESULTS

The results showed a PPV of 58%. Variables predicting negative culture included younger patients, males, and a reason for the visit to the emergency department of a fall/syncope or other.

CONCLUSIONS

Further optimization is needed for URTC criteria and the appropriateness of ordering UAs to reduce operational laboratory costs and inappropriate antibiotic treatment.

Antibiotic prescription patterns in patients with suspected urinary tract infections in Ecuador

BACKGROUND

Urinary tract infections (UTI) are among the most common cause to prescribe antibiotics in primary care. Diagnosis is based on the presence of clinical symptoms in combination with the results of laboratory tests. Antibiotic therapy is the primary approach to the treatment of UTIs; however, some studies indicate that therapeutics in UTIs may be suboptimal, potentially leading to therapeutic failure and increased bacterial resistance.

METHODS

This study aimed to analyze the antibiotic prescription patterns in adult patients with suspected UTIs and to evaluate the appropriateness of the antibiotic prescription. This is a cross-sectional study of patients treated in outpatient centers and in a second-level hospital of the Ministry of Public Health (MOPH) in a city in Ecuador during 2019. The International Classification of Disease Tenth Revision (ICD-10) was used for the selection of the acute UTI cases. The patients included in this study were those treated by family, emergency, and internal medicine physicians.

RESULTS

We included a total of 507 patients in the analysis and 502 were prescribed antibiotics at first contact, constituting an immediate antibiotic prescription rate of 99.01%. Appropriate criteria for antibiotic prescription were met in 284 patients, representing an appropriate prescription rate of 56.02%. Less than 10% of patients with UTI had a urine culture. The most frequently prescribed antibiotics were alternative antibiotics (also known as second-line antibiotics), such as ciprofloxacin (50.39%) and cephalexin (23.55%). Factors associated with inappropriate antibiotic prescribing for UTIs were physician age over forty years, OR: 2.87 (95% CI, 1.65-5.12) p<0.0001, medical care by a general practitioner, OR: 1.89 (95% CI, 1.20-2.99) p = 0.006, not using point-of-care testing, OR: 1.96 (95% CI, 1.23-3.15) p = 0.005, and care at the first level of health, OR: 15.72 (95% CI, 8.57-30.88) p<0.0001.

CONCLUSIONS

The results of our study indicate an appropriate prescription rate of 56.02%. Recommended antibiotics such as nitrofurantoin and fosfomycin for UTIs are underutilized. The odds for inappropriate antibiotic prescription were 15.72 times higher at the first level of care compared to the second. Effective strategies are needed to improve the diagnosis and treatment of UTIs.

[Diagnostic Stewardship - The right test for the right patient with the right consequences]

In 2023, the Society for Healthcare Epidemiology of America (SHEA) Task Force issued a practice recommendation on the integration of diagnostic stewardship into antibiotic stewardship (ABS) programs, which focuses on optimizing sample collection, processing, and reporting to ensure a correct test result on the one hand, and on the justifying indication to perform diagnostics on the other.Unnecessary microbiological or serological tests produce results that can then lead to unnecessary further tests for clarification or unnecessary antibiotic administration. A classic example is "routine" urine cultures before non-urological, surgical interventions, which often lead to the treatment of asymptomatic bacteriuria. Every microbiological diagnosis must therefore be preceded by a specific question, whereby screening examinations from epidemiological questions must be clearly distinguished from clinical requirements. A particular problem is the distinction between contamination, colonization and infection, especially when samples are taken from catheters or drains. These materials should always be evaluated with extreme caution and may only be accepted at all if the clinical question is clear and subject to this very reservation. This article summarizes the existing evidence on diagnostic stewardship interventions and recommendations on their implementation, extrapolating the international literature to the specifications of the German health care system.

Is it meaningful to apply midstream urine culture to urine specimens with negative Gram stain results?

INTRODUCTION

Gram staining is a convenient method for bacterial estimation. Urine culture is typically used to diagnose urinary tract infections. Therefore, urine culture is also performed on Gram stain-negative urine specimens. However, the frequency of uropathogen identification in these samples remains unclear.

METHODS

From 2016 to 2019, we retrospectively compared the results of Gram staining and urine culture tests on midstream urine specimens submitted for the diagnosis of urinary tract infections to confirm the significance of urine culture on Gram stain-negative specimens. Analysis was performed according to the patients' sex and age, and the frequency of uropathogen identification in the culture was examined.

RESULTS

A total of 1763 urine specimens (women, 931; men, 832) were collected. Of these, 448 (25.4%) were not positive on Gram staining but were positive on culture. In specimens without bacteria on Gram staining, the frequencies of specimens with uropathogens detected on culture were 20.8% (22/160) in women aged <50 years, 21.4% (71/332) in women aged ≥50 years, 2.0% (2/97) in men aged <50 years, and 7.8% (39/499) in men aged ≥50 years.

CONCLUSIONS

In men aged <50 years, the frequency of uropathogenic bacteria identification by urine culture was low in Gram stain-negative specimens. Therefore, urine cultures may be excluded from this group. In contrast, in women, a small number of Gram stain-negative specimens showed significant culture results for the diagnosis of urinary tract infection. Therefore, urine culture should not be omitted in women without careful consideration.

Urinalysis exhibits excellent predictive capacity for the absence of urinary tract infection

OBJECTIVES

To assess predictive value of urinalysis for negative urine culture and absence of urinary tract infection, re-evaluate the microbial growth threshold for positive urine culture result, and describe antimicrobial resistance features. Urine culture is associated with 27% of U.S. hospitalizations, and unnecessary antibiotic prescription is a main antibiotic resistance contributor.

SUBJECTS AND METHODS

Urinalyses with urine culture from women ages 18-49 from 2013 to 2020 were studied. Clinically-diagnosed urinary tract infection (CUTI) was defined as 1) uropathogen growth, 2) documented diagnosis of urinary tract infection, and 3) antibiotic prescription. Sensitivity, specificity, and diagnostic predictive values were used to assess urinalysis performance in predicting isolation of a uropathogen by culture and in detection of CUTI.

RESULTS

12,252 urinalyses were included. 41% of urinalyses were associated with positive urine culture and 1287 (10.5%) with CUTI. Negative urinalysis exhibited high predictive accuracy for negative urine culture (specificity 90.3%, PPV 87.3%) and absence of CUTI (specificity 92.2%, PPV 97.4%). 24% of patients not meeting the CUTI definition were still prescribed antibiotics. 22% of cultures associated with CUTI exhibited growth less than 100,000 CFU/ml. Escherichia coli was implemented as causing 70% of CUTIs, and 4.2% of these produced an extended spectrum beta-lactamase.

CONCLUSIONS

Negative urinalysis exhibits high predictive accuracy for absence of CUTI. A reporting threshold of 10,000 CFU/ml is more clinically appropriate than a 100,000 CFU/ml cutpoint. Reflex culture based on urinalysis results could complement clinical judgement and improve laboratory and antibiotic stewardship in pre-menopausal women.

Leveraging diagnostic stewardship within antimicrobial stewardship programmes

Novel diagnostic stewardship in infectious disease consists of interventions that modify ordering, processing, and reporting of diagnostic tests to provide the right test for the right patient, prompting the right action. The interventions work upstream and synergistically with traditional antimicrobial stewardship efforts. As diagnostic stewardship continues to gain public attention, it is critical that antimicrobial stewardship programmes not only learn how to effectively leverage diagnostic testing to improve antimicrobial use but also ensure that they are stakeholders and leaders in developing new diagnostic stewardship interventions within their institutions. This review will discuss the need for diagnostic and antimicrobial stewardship, the interplay of diagnostic and antimicrobial stewardship, evidence of benefit to antimicrobial stewardship programmes, and considerations for successfully engaging in diagnostic stewardship interventions. This article is part of the Antibiotic stewardship Special Issue: https://www.drugsincontext.com/special_issues/antimicrobial-stewardship-a-focus-on-the-need-for-moderation.

Optimizing reflex urine cultures: Using a population-specific approach to diagnostic stewardship

BACKGROUND

Clinicians and laboratories routinely use urinalysis (UA) parameters to determine whether antimicrobial treatment and/or urine cultures are needed. Yet the performance of individual UA parameters and common thresholds for action are not well defined and may vary across different patient populations.

METHODS

In this retrospective cohort study, we included all encounters with UAs ordered 24 hours prior to a urine culture between 2015 and 2020 at 3 North Carolina hospitals. We evaluated the performance of relevant UA parameters as potential outcome predictors, including sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). We also combined 18 different UA criteria and used receiver operating curves to identify the 5 best-performing models for predicting significant bacteriuria (≥100,000 colony-forming units of bacteria/mL).

RESULTS

In 221,933 encounters during the 6-year study period, no single UA parameter had both high sensitivity and high specificity in predicting bacteriuria. Absence of leukocyte esterase and pyuria had a high NPV for significant bacteriuria. Combined UA parameters did not perform better than pyuria alone with regard to NPV. The high NPV ≥0.90 of pyuria was maintained among most patient subgroups except females aged ≥65 years and patients with indwelling catheters.

CONCLUSION

When used as a part of a diagnostic workup, UA parameters should be leveraged for their NPV instead of sensitivity. Because many laboratories and hospitals use reflex urine culture algorithms, their workflow should include clinical decision support and or education to target symptomatic patients and focus on populations where absence of pyuria has high NPV.

Recommendations for change in infection prevention programs and practice

Fifty years of evolution in infection prevention and control programs have involved significant accomplishments related to clinical practices, methodologies, and technology. However, regulatory mandates, and resource and research limitations, coupled with emerging infection threats such as the COVID-19 pandemic, present considerable challenges for infection preventionists. This article provides guidance and recommendations in 14 key areas. These interventions should be considered for implementation by United States health care facilities in the near future.

Applying Diagnostic Stewardship to Proactively Optimize the Management of Urinary Tract Infections

A urinary tract infection is amongst the most common bacterial infections in the community and hospital setting and accounts for an estimated 1.6 to 2.14 billion in national healthcare expenditure. Despite its financial impact, the diagnosis is challenging with urine cultures and antibiotics often inappropriately ordered for non-specific symptoms or asymptomatic bacteriuria. In an attempt to limit unnecessary laboratory testing and antibiotic overutilization, several diagnostic stewardship initiatives have been described in the literature. We conducted a systematic review with a focus on the application of molecular and microbiological diagnostics, clinical decision support, and implementation of diagnostic stewardship initiatives for urinary tract infections. The most successful strategies utilized a bundled, multidisciplinary, and multimodal approach involving nursing and physician education and feedback, indication requirements for urine culture orders, reflex urine culture programs, cascade reporting, and urinary antibiograms. Implementation of antibiotic stewardship initiatives across the various phases of laboratory testing (i.e., pre-analytic, analytic, post-analytic) can effectively decrease the rate of inappropriate ordering of urine cultures and antibiotic prescribing in patients with clinically ambiguous symptoms that are unlikely to be a urinary tract infection.

Comparison of Urine Flow Cytometry on the UF-1000i System and Urine Culture of Urine Samples from Urological Patients

Introduction

The aims of this study were to evaluate urine flow cytometry (UFC) as a tool to screen urine samples of urological patients for bacteriuria and to compare UFC and dipstick analysis with urine culture in a patient cohort at a urological department of a university hospital.

Methods and Material

We screened 662 urine samples from urological patients (75.2% male; 80.7% inpatients; mean age 58 years). UFC results were compared to microbiological urine culture.

Results

The accuracy in using the UFC-based parameters for detecting cultural bacteriuria was 91.99% and 88.97% for ≥10⁵ colony-forming units (CFU)/mL and ≥10⁴ CFU/mL, respectively. UFC and leukocyte dipstick analysis measured leukocyturia similarly (Pearson correlation coefficient 0.87, p value <0.01%), but dipstick analysis scored less accurately on bacteriuria (accuracy 59.37% and 62.69%). UFC remained effective in subgroup analysis of patients of both sexes and with different urological conditions with its overall use only slightly impaired when assessing gross hematuria (NPV 84.62% for ≥10⁴ CFU/mL). UFC also reliably removed those urine samples below cutoffs with negative predictive values of 99.28% for ≥10⁵ CFU/mL and 95.86% for ≥10⁴ CFU/mL.

Conclusion

Counting bacteria with UFC is an accurate and rapid method to determine significant bacteriuria in urological patients and is superior to dipstick analysis or indirect surrogate parameters such as leukocyturia. When UFC is available, we recommend it to be used for the diagnosis of bacteriuria over findings obtained by dipstick analysis.

The Five Ds of Outpatient Antibiotic Stewardship for Urinary Tract Infections

Urinary tract infections (UTI) are one of the most common indications for antibiotic prescriptions in the outpatient setting. Given rising rates of antibiotic resistance among uropathogens, antibiotic stewardship is critically needed to improve outpatient antibiotic use, including in outpatient clinics (primary care and specialty clinics) and emergency departments. Outpatient clinics are in general a neglected practice area in antibiotic stewardship programs, yet most antibiotic use in the United States is in the outpatient setting. This article provides a comprehensive review of antibiotic stewardship strategies for outpatient UTI in the adult population, with a focus on the "five Ds" of stewardship for UTI, including right diagnosis, right drug, right dose, right duration, and de-escalation. Stewardship interventions that have shown success for improving prescribing for outpatient UTI are discussed, including diagnostic stewardship strategies, such as reflex urine cultures, computerized decision support systems, and modified reporting of urine culture results. Among the many challenges to achieving stewardship for UTI in the outpatient setting, some of the most important are diagnostic uncertainty, increasing antibiotic resistance, limitations of guidelines, and time constraints of stewardship personnel and front-line providers. This article presents a stewardship framework, built on current evidence and expert opinion, that clinicians can use to guide their own outpatient management of UTI.

Optimal Urine Culture Diagnostic Stewardship Practice- Results from an Expert Modified-Delphi Procedure

BACKGROUND

Urine cultures are nonspecific for infection and often lead to misdiagnosis of urinary tract infection and unnecessary antibiotics. Diagnostic stewardship is a set of procedures that modifies test ordering, processing, and reporting in order to optimize diagnosis and downstream treatment. This study aimed to develop expert guidance on best practices for urine culture diagnostic stewardship.

METHODS

A RAND-modified Delphi approach with a multidisciplinary expert panel was used to ascertain diagnostic stewardship best practices. Clinical questions to guide recommendations were grouped in three thematic areas (ordering, processing, reporting) in practice settings of emergency department, inpatient, ambulatory, and long-term care. Fifteen experts ranked recommendations on a 9-point Likert scale. Recommendations on which the panel did not reach agreement were discussed in a virtual meeting, and a then second round of ranking by email was completed. After secondary review of results and panel discussion, a series of guidance statements was developed.

RESULTS

165 questions were reviewed with the panel reaching agreement on 104, leading to 18 overarching guidance statements. The following strategies were recommended to optimize ordering urine cultures: requiring documentation of symptoms, alerts to discourage ordering in the absence of symptoms, and cancelling repeat cultures. For urine culture processing, conditional reflex urine cultures and urine white blood cell as criteria were supported. For urine culture reporting, appropriate practices included nudges to discourage treatment under specific conditions and selective reporting of antibiotics to guide therapy decisions.

CONCLUSIONS

These 18 guidance statements can optimize use of the imperfect urine culture for better patient outcomes.

Revisiting approaches to and considerations for urinalysis and urine culture reflexive testing

Urinalysis is considered the world's oldest laboratory test. Today, many laboratories use macroscopic urinalysis as a screening tool to determine when to subject urine samples for a microscopic urinalysis and/or bacterial culture. While reflexive urine microscopy has been practiced for decades, and reflexive urine culture, more recently, evidence-based guidelines regarding optimal reflexive criteria and workflows are lacking. Standard approaches are hindered, in part, by a lack of harmonization of urinalysis and urine culture practices, heterogeneity in patient populations that are studied, and lack of provider adherence to recommended practices. This review summarizes studies that have evaluated the performance of reflexive urine microscopy and reflexive urine culture, particularly in the context of urinary tract infections. It also examines reported clinical outcomes from reflexive urinalysis interventions and their impact on antibiotic stewardship efforts. Finally, it discusses laboratory operational considerations for the implementation of reflexive algorithms.

Deconstructing the urinalysis: A novel approach to diagnostic and antimicrobial stewardship

The extensive use of the urinalysis for screening and monitoring in diverse clinical settings usually identifies abnormal urinalysis parameters in patients with no suspicion of urinary tract infection, which in turn triggers urine cultures, inappropriate antimicrobial use, and associated harms like Clostridioides difficile infection. We highlight how urinalysis is misused, and suggest deconstructing it to better align with evolving patterns of clinical use and the differential diagnosis being targeted. Reclassifying the urinalysis components into infectious and non-infectious panels and interpreting urinalysis results in the context of individual patient’s pretest probability of disease is a novel approach to promote proper urine testing and antimicrobial stewardship, and achieve better outcomes.

Quality Improvement Interventions and Implementation Strategies for Urine Culture Stewardship in the Acute Care Setting: Advances and Challenges

PURPOSE OF REVIEW

The goal of this article is to highlight how and why urinalyses and urine cultures are misused, review quality improvement interventions to optimize urine culture utilization, and highlight how to implement successful, sustainable interventions to improve urine culture practices in the acute care setting.

RECENT FINDINGS

Quality improvement initiatives aimed at reducing inappropriate treatment of asymptomatic bacteriuria often focus on optimizing urine test utilization (i.e., urine culture stewardship). Urine culture stewardship interventions in acute care hospitals span the spectrum of quality improvement initiatives, ranging from strong systems-based interventions like suppression of urine culture results to weaker interventions that focus on clinician education alone. While most urine culture stewardship interventions have met with some success, overall results are mixed, and implementation strategies to improve sustainability are not well understood.

SUMMARY

Successful diagnostic stewardship interventions are based on an assessment of underlying key drivers and focus on multifaceted and complementary approaches. Individual intervention components have varying impacts on effectiveness, provider autonomy, and sustainability. The best urine culture stewardship strategies ultimately include both technical and socio-adaptive components with long-term, iterative feedback required for sustainability.

Correlation of Chemical Urinalysis to Microscopic Urinalysis and Urine Culture: Implications for Reflex Urinalysis Workflows

BACKGROUND

Urinalysis (UA) reflex testing approaches, which offer potential for savings in labor and result turnaround time, may rely on the performance of a chemical UA screen to determine which urine samples need microscopic UA and/or urine culture. We correlated chemical UA, microscopic UA, and urine culture results to determine the performance of chemical UA as a screening tool for reflex testing approaches.

METHODS

Consecutive UA results for 9127 tests (simultaneous chemical UA and microscopic UA) were retrospectively reviewed and correlated. Urine culture results were also correlated for 3127 samples that had urine culture ordered within 24 h of UA. Positivity criteria for each UA method were predefined.

RESULTS

Chemical UA yielded the following performance specifications for predicting microscopic findings: 93.0% sensitivity, 56.9% specificity, 64.7% positive predictive value, 90.5% negative predictive value. 3.2% of samples were negative by chemical UA but positive by microscopic UA. Of the samples with urine culture results available, 6.3% were negative by chemical UA but had clinically-significant positive urine cultures.

CONCLUSIONS

Reflex testing of microscopic UA and/or urine culture dependent from chemical UA results provides a feasible opportunity to reduce unnecessary testing.

Optimizing rapid diagnostics and diagnostic stewardship in Gram-negative bacteremia

Antimicrobial resistance remains a high global concern, as it is associated with prolonged hospitalizations, increased morbidity and mortality, and escalating healthcare-related costs. Rapid diagnostic technology (RDT) has become the cornerstone in achieving prompt blood culture results providing a quicker initiation of optimal therapy, decreased mortality, and decreased spread of resistance. To maximize the benefits of RDTs, antimicrobial stewardship programs must implement a diagnostic stewardship (DS) subgroup to optimize communication, education, and interpretation of RDT results within the healthcare system. The DS subgroup is necessary to evaluate the technologies available, better integrate the selected technologies into the healthcare system, and develop innovative and appropriate use to improve patient outcomes.

Evaluation of a Novel Light Scattering Methodology for the Detection of Pathogenic Bacteria in Urine

BACKGROUND

Urine culture, the gold standard for detecting and identifying bacteria in urine, is one of the highest volume tests in many microbiology laboratories. The inability to accurately predict which patients would benefit from culture leads not only to monopolization of laboratory resources, but also to unnecessary antimicrobial exposure as patients receive empirical treatment for suspected or presumed urinary tract infections (UTI) while awaiting culture results. A common approach to decrease unnecessary urine culture is screening samples using urinalysis (UA) parameters to determine those that should proceed to culture (reflex). In this study, we compared the performance of a novel uropathogen detection method to urinalysis for purposes of UTI screening.

METHODS

Urine specimens submitted for culture (n = 194) were evaluated by urinalysis and a novel light scattering device (BacterioScan 216Dx UTI System) capable of detecting the presence of bacteria in urine. Sensitivity and specificity for prediction of a positive urine culture by UA and 216Dx were determined relative to urine culture results. A positive urine culture was defined as growth in culture of one or two uropathogens at concentrations of ≥50,000 CFU/mL.

RESULTS

194 urine samples were evaluated by UA, 216Dx, and urine culture. The 216Dx demonstrated a 100% [95%CI: 88.43%-100.0%] sensitivity and 81.71% [95%CI: 74.93%-87.30%] specificity for the detection of bacteriuria, vs UA with a sensitivity of 86.67% [95%CI 69.28%-96.24%] and specificity of 71.95% [95%CI: 64.41%-78.68%] when compared to urine culture (diagnostic reference method).

CONCLUSIONS

BacterioScan allows for an alternative method of screening with satisfactory sensitivity and improved specificity that may facilitate a reduction of unnecessary cultures. Additional studies are required to determine if a concomitant decrease in inappropriate antibiotic use can be realized with the 216Dx technology.

Assessment of Testing and Treatment of Asymptomatic Bacteriuria Initiated in the Emergency Department

Background

Reducing antibiotic use in patients with asymptomatic bacteriuria (ASB) has been inpatient focused. However, testing and treatment is often started in the emergency department (ED). Thus, for hospitalized patients with ASB, we sought to identify patterns of testing and treatment initiated by emergency medicine (EM) clinicians and the association of treatment with outcomes.

Methods

We conducted a 43-hospital, cohort study of adults admitted through the ED with ASB (February 2018-February 2020). Using generalized estimating equation models, we assessed for (1) factors associated with antibiotic treatment by EM clinicians and, after inverse probability of treatment weighting, (2) the effect of treatment on outcomes.

Results

Of 2461 patients with ASB, 74.4% (N = 1830) received antibiotics. The EM clinicians ordered urine cultures in 80.0% (N = 1970) of patients and initiated treatment in 68.5% (1253 of 1830). Predictors of EM clinician treatment of ASB versus no treatment included dementia, spinal cord injury, incontinence, urinary catheter, altered mental status, leukocytosis, and abnormal urinalysis. Once initiated by EM clinicians, 79% (993 of 1253) of patients remained on antibiotics for at least 3 days. Antibiotic treatment was associated with a longer length of hospitalization (mean 5.1 vs 4.2 days; relative risk = 1.16; 95% confidence interval, 1.08-1.23) and Clostridioides difficile infection (CDI) (0.9% [N = 11] vs 0% [N = 0]; P = .02).

Conclusions

Among hospitalized patients ultimately diagnosed with ASB, EM clinicians commonly initiated testing and treatment; most antibiotics were continued by inpatient clinicians. Antibiotic treatment was not associated with improved outcomes, whereas it was associated with prolonged hospitalization and CDI. For best impact, stewardship interventions must expand to the ED.

Evaluation of evidence-based urinalysis reflex to culture criteria: Impact on reducing antimicrobial usage

OBJECTIVES

To implement evidence-based urinalysis (UA) reflex criteria and to evaluate the impact of the intervention on reducing unnecessary antibiotic usage.

METHODS

A prospective intervention study was conducted on 4130 urine samples that were subjected to UA during March to May 2020. Results were analyzed in order to evaluate the effectiveness of newly implemented evidence-based criteria in predicting positive urine cultures. The intervention involved implementing evidence-based UA reflex criteria to ensure a high predictive value of the UA reflex parameters. Multivariable logistic regression was utilized to evaluate the effectiveness of these UA parameters in predicting positive urine cultures and to assess the impact of the new UA criteria on antibiotic usage.

RESULTS

A total of 4130 patient samples were included in the study; 60.1% (n = 2484) were from female patients and 39.9% (n = 1646) were from male patients. The total number of negative urine reflex samples was 3116, which accounted for 75.4% of the total UA reflex samples. In contrast, 24.6% of the urine reflex samples (n = 1014) returned positive UA results and were reflexed to urine culture. Among the urine samples that were cultured, 9% (n = 91) were negative urine cultures, while 91.0% (n = 923) were positive urine cultures. Chi-square analysis indicated highly statistically significant associations between the combination parameters of (≥5 white blood cells (WBCs) and positive nitrite) and positive urine cultures (Chi-square = 516.428, p < 0.001) and (≥5 WBCs and moderate or large esterase) and positive urine cultures (Chi-square = 503.387, p < 0.001). Additionally, Chi-square analysis indicated a highly statistically significant association between the combination parameters of (≥5 WBCs and ≥1 bacteria) and positive urine cultures (Chi-square = 434.806, p < 0.001). The statistical analysis showed that the implementation of evidence-based UA reflex criteria significantly decreased the number of urine cultures performed and potentially decreased the number of patients inappropriately treated with antibiotics from 45.1% to 9%.

CONCLUSIONS

In conclusion, ≥5 WBCs and positive nitrite yielded the highest positive predictive value of 98.00% and showed a highly significant association with positive urine cultures. It was observed that the new UA reflex criteria are highly effective in predicting positive urine cultures, thus potentially resulting in the reduction of unnecessary antibiotic usage.

A Pilot Study to Evaluate the Impact of a Nurse-Driven Urine Culture Diagnostic Stewardship Intervention on Urine Cultures in the Acute Care Setting

BACKGROUND

The role of nurses in diagnostic stewardship in hospitals remains largely unknown.

METHODS

In this before-after study, researchers assessed the impact of a nurse-driven urine culture (UrCx) stewardship intervention for adults with and without urinary catheters on a general medicine unit of a large hospital. The intervention included education on principles of diagnostic stewardship, identification of a nurse champion to serve as liaison between nursing and the antibiotic stewardship program, and implementation of an algorithm to guide discussions with hospitalists about situations when UrCx may not be needed. The primary outcome was the total number of UrCx. The secondary outcome was the rate of inappropriate UrCx. Changes in UrCx rates per 100 patient-days before and after the intervention were calculated using incidence rate ratios (IRRs). Balancing metrics included readmission within 30 days of unit discharge, length of hospital stay, and all-cause in-hospital mortality.

RESULTS

With the intervention, the mean UrCx rate per 100 patient-days decreased from 2.30 to 1.52 (IRR = 0.66, 95% confidence interval [CI] = 0.50-0.87, p < 0.01), while in the control unit it increased from 2.17 to 3.10 (IRR = 1.50, 95% CI = 1.22-1.84, p < 0.01). In the intervention unit, the rate of inappropriate UrCx was 0.83 and 0.71 before and after algorithm implementation (IRR = 0.88, 95% CI = 0.58-1.33, p = 0.55).

CONCLUSION

Nursing education and a clinical tool to enhance discussions on the necessity of UrCx among nurses and hospitalists were associated with a reduction in UrCx.

How Testing Drives Treatment in Asymptomatic Patients: Level of Pyuria Directly Predicts Probability of Antimicrobial Prescribing

BACKGROUND

Urinalysis is a readily available test often used for screening. Pyuria is a common finding in asymptomatic patients; however, it is unknown how often identification of pyuria in the absence of confirmatory cultures leads to antimicrobial prescribing. The objective of this study was to measure the association between pyuria and antimicrobial initiation during the perioperative period and assess harms versus benefits of treatment.

METHODS

A retrospective cohort of preoperative patients within the national healthcare system during the period 1 October 2008-30 September 2013 who had a urinalysis performed during the 30-day preoperative period was created; patients with positive urine cultures were excluded. The primary exposure was pyuria on preoperative urinalysis. The primary outcome was antimicrobial initiation. Secondary outcomes included postoperative surgical site (SSI), urinary tract (UTI), and Clostridioides difficile infections. Trend and logistic regression analyses were performed.

RESULTS

Among 41 373 patients, 3617 had pyuria. 887 (24.5%) patients with pyuria received antimicrobials versus 1918 (5.1%) patients without pyuria. As the degree of pyuria increased, the odds of receiving antimicrobials also increased linearly (low, 14.7%; moderate, 24.0%; high pyuria, 37.4%). Preoperative pyuria was associated with postoperative C. difficile infections (aOR, 1.7; 95% CI, 1.2-2.4); risk was higher in patients who received antimicrobials (aOR, 2.4; 1.7-3.4). Pyuria was not associated with SSI but was associated with increases in UTI after orthopedic and vascular procedures; this risk was not mitigated by antimicrobial therapy.

CONCLUSIONS

Urine screening during the preoperative period is a low-value intervention that increases antimicrobial exposure but does not improve postoperative outcomes.

Reducing inappropriate urine cultures through a culture standardization program

BACKGROUND

The objective of this study was to evaluate the impact of a urine culture standardization program that included order indications and urinalysis (U/A) with reflexive culture. The program applied to all adult and pediatric inpatients at an academic medical center; emergency department and ambulatory clinic patients were excluded.

METHODS

The analysis compared outcomes in the pre-implementation (January 2015-May 2016) and post-implementation (July 2016-September 2017) periods. The primary outcomes were urine culture and U/A orders per 1,000 patient days, catheter-associated urinary tract infection (CAUTI) rate per 1,000 catheter days, and urine culture contamination rate per 1,000 patient days. Catheter standardized utilization ratios (SURs) were also examined.

RESULTS

The intervention was associated with a significant decrease in urine culture rates by 6.9 cultures per 1,000 patient days (95% CI -4.44, -9.44; P < .0001). The U/A testing rate per 1,000 patient days significantly increased pre-intervention, was not affected acutely by the intervention institution, and significantly decreased post-implementation. The CAUTI rate was not significantly changed by the intervention but did significantly increase post-implementation by 0.2 per 1,000 catheter days (95% CI 0.01, 0.47; P = .04); SURs significantly decreased (0.03; 95% CI -0.003, -0.05; P = .03); and the urine culture contamination rate per month showed no significant change. Sixty-four percent of urine cultures ordered using the reflexive test did not reflex to culture by U/A criteria.

CONCLUSIONS

A urine culture standardization program led to a significant reduction in urine cultures and did not lead to an increase in U/A testing rates. CAUTI rates increased post-implementation, which may have been confounded by reduced catheter utilization.

Risk Factors and Outcomes Associated With Treatment of Asymptomatic Bacteriuria in Hospitalized Patients

IMPORTANCE

Treatment of asymptomatic bacteriuria (ASB) with antibiotics is a common factor in inappropriate antibiotic use, but risk factors and outcomes associated with treatment of ASB in hospitalized patients are not well defined.

OBJECTIVE

To evaluate factors associated with treatment of ASB among hospitalized patients and the possible association between treatment and clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted from January 1, 2016, through February 1, 2018, at 46 hospitals participating in the Michigan Hospital Medicine Safety Consortium. A total of 2733 hospitalized medical patients with ASB, defined as a positive urine culture without any documented signs or symptoms attributable to urinary tract infection, were included in the analysis.

EXPOSURES

One or more antibiotic dose for treatment of ASB.

MAIN OUTCOMES AND MEASURES

Estimators of antibiotic treatment of ASB. Secondary outcomes included 30-day mortality, 30-day hospital readmission, 30-day emergency department visit, discharge to post-acute care settings, Clostridioides difficile infection (formerly known as Clostridium difficile) at 30 days, and duration of hospitalization after urine testing.

RESULTS

Of 2733 patients with ASB, 2138 were women (78.2%); median age was 77 years (interquartile range [IQR], 66-86 years). A total of 2259 patients (82.7%) were treated with antibiotics for a median of 7 days (IQR, 4-9 days). Factors associated with ASB treatment included older age (odds ratio [OR], 1.10 per 10-year increase; 95% CI, 1.02-1.18), dementia (OR, 1.57; 95% CI, 1.15-2.13), acutely altered mental status (OR, 1.93; 95% CI, 1.23-3.04), urinary incontinence (OR, 1.81; 95% CI, 1.36-2.41), leukocytosis (white blood cell count >10 000/μL) (OR, 1.55; 95% CI, 1.21-2.00), positive urinalysis (presence of leukocyte esterase or nitrite, or >5 white blood cells per high-power field) (OR, 2.83; 95% CI, 2.05-3.93), and urine culture with a bacterial colony count greater than 100 000 colony-forming units per high-power field (OR, 2.30; 95% CI, 1.83-2.91). Treatment of ASB was associated with longer duration of hospitalization after urine testing (4 vs 3 days; relative risk, 1.37; 95% CI, 1.28-1.47). No other differences in secondary outcomes were identified after propensity weighting.

CONCLUSIONS AND RELEVANCE

Hospitalized patients with ASB commonly receive inappropriate antibiotic therapy. Antibiotic treatment did not appear to be associated with improved outcomes; rather, treatment may be associated with longer duration of hospitalization after urine testing. To possibly reduce inappropriate antibiotic use, stewardship efforts should focus on improving urine testing practices and management strategies for elderly patients with altered mental status.

Diagnostic Bacteriology in District Hospitals in Sub-Saharan Africa: At the Forefront of the Containment of Antimicrobial Resistance

This review provides an update on the factors fuelling antimicrobial resistance and shows the impact of these factors in low-resource settings. We detail the challenges and barriers to integrating clinical bacteriology in hospitals in low-resource settings, as well as the opportunities provided by the recent capacity building efforts of national laboratory networks focused on vertical single-disease programmes. The programmes for HIV, tuberculosis and malaria have considerably improved laboratory medicine in Sub-Saharan Africa, paving the way for clinical bacteriology. Furthermore, special attention is paid to topics that are less familiar to the general medical community, such as the crucial role of regulatory frameworks for diagnostics and the educational profile required for a productive laboratory workforce in low-resource settings. Traditionally, clinical bacteriology laboratories have been a part of higher levels of care, and, as a result, they were poorly linked to clinical practices and thus underused. By establishing and consolidating clinical bacteriology laboratories at the hospital referral level in low-resource settings, routine patient care data can be collected for surveillance, antibiotic stewardship and infection prevention and control. Together, these activities form a synergistic tripartite effort at the frontline of the emergence and spread of multi-drug resistant bacteria. If challenges related to staff, funding, scale, and the specific nature of clinical bacteriology are prioritized, a major leap forward in the containment of antimicrobial resistance can be achieved. The mobilization of resources coordinated by national laboratory plans and interventions tailored by a good understanding of the hospital microcosm will be crucial to success, and further contributions will be made by market interventions and business models for diagnostic laboratories. The future clinical bacteriology laboratory in a low-resource setting will not be an "entry-level version" of its counterparts in high-resource settings, but a purpose-built, well-conceived, cost-effective and efficient diagnostic facility at the forefront of antimicrobial resistance containment.

Knowledge and Practices of Physicians and Nurses Related to Urine Cultures in Catheterized Patients: An Assessment of Adherence to IDSA Guidelines

Background

A positive urine culture often drives initiation of antimicrobials even in the absence of symptoms. Our objectives were to evaluate the knowledge and practice patterns related to ordering urine cultures in patients with indwelling urinary catheters.

Methods

We performed chart reviews of catheter-associated urinary tract infections (CAUTIs) at our academic health care system between October 1, 2015, and September 30, 2017, to assess practice patterns related to the assessment of potential CAUTIs. Following this, we surveyed physicians and nurses about indications for ordering urine cultures in catheterized patients between January 11, 2018, and April 17, 2018. The accuracy of these indications was assessed based on Infectious Diseases Society of America CAUTI and asymptomatic bacteriuria guidelines.

Results

On chart review, we identified 184 CAUTIs in 2 years. In 159 episodes (86%), urine cultures were ordered inappropriately. In 114 episodes (62%), CAUTI criteria were met by “pan-culturing” rather than symptom-directed testing. Twenty cases (11%) experienced partial or delayed management of other infections, drug adverse events, and Clostridioides difficile infections (CDIs). On our survey, we received 405 responses, for a response rate of 45.3%. Mean scores varied by occupation and level of training. Nurses were more likely than physicians to consider change in appearance (61% vs 23%; P < .05) and odor (74% vs 42%; P < .05) of urine as indications to order urine cultures.

Conclusions

Our data reveal specific knowledge gaps among physicians and nurses related to ordering urine cultures in catheterized patients. The practice of pan-culturing and inappropriate urine culture orders may contribute to overdiagnosis of surveillance CAUTIs, delay in diagnosis of alternative infections, and excess CDIs.

The evolution of catheter-associated urinary tract infection (CAUTI): Is it time for more inclusive metrics?

Catheter-associated urinary tract infection (CAUTI) has long been considered a preventable healthcare-associated infection. Many federal agencies, the Centers for Medicare and Medicaid Services (CMS), and public and private healthcare organizations have implemented strategies aimed at preventing CAUTIs. To monitor progress in CAUTI prevention, the National Healthcare Safety Network (NHSN) CAUTI metric has been adopted nationally as the primary outcome measure and has been refined over the past decades. However, this surveillance metric may underestimate infectious and noninfectious catheter harm. We suggest evolving to more inclusive performance metrics to better reflect quality improvement efforts underway in hospitals. The standardized device utilization ratio (SUR) provides a good surrogate for preventable catheter harm. On the other hand, a population-based metric that combines both standardized infection ratio (SIR) and SUR would address both infectious and noninfectious harm, while adjusting for population risk. Finally, electronically captured catheter-associated bacteriuria may contribute essential information on local testing stewardship.

Evaluation of the BacterioScan 216Dx for Standalone Preculture Screen of Preserved Urine Specimens in a Clinical Setting

Background

The BacterioScan 216Dx laser microbial growth monitoring system was evaluated as an option for preurine culture screening of preserved urine specimens at an acute care medical center.

Methods

The BacterioScan 216Dx system performance characteristics and the economic impact (cost effectiveness) for the laboratory were assessed. Urinalysis performance compared to urine culture was assessed if urinalysis was ordered as part of the patient care set.

Results

When compared to urine culture, the BacterioScan had an overall performance with corresponding 95% confidence intervals of 76% (68-83) sensitivity, 84% (80-87) specificity, 55% (48-63) positive predictive value, and 93% (90-95) negative predictive value for 610 randomly selected preserved urine specimens. Urinalysis compared to urine culture overall performance was 59% (48-69) sensitivity, 87% (83-90) specificity, 53% (43-63) positive predictive value, 89% (86-92) negative predictive value for 414 urine specimens.

Conclusions

While the system did improve the turnaround time to a negative report, adoption of the BacterioScan system would increase the reagent budget for laboratory urine culture by 2.34 times the current cost, potentially making BacterioScan prohibitive in a budget restricted environment. Additionally, performance when compared to traditional urine culture was less than acceptable for a diagnostic laboratory to use as a stand-alone urinary tract infection screen.

Reducing unnecessary culturing: a systems approach to evaluating urine culture ordering and collection practices among nurses in two acute care settings

Background

Inappropriate ordering and acquisition of urine cultures leads to unnecessary treatment of asymptomatic bacteriuria (ASB). Treatment of ASB contributes to antimicrobial resistance particularly among hospital-acquired organisms. Our objective was to investigate urine culture ordering and collection practices among nurses to identify key system-level and human factor barriers and facilitators that affect optimal ordering and collection practices.

Methods

We conducted two focus groups, one with ED nurses and the other with ICU nurses. Questions were developed using the Systems Engineering Initiative for Patient Safety (SEIPS) framework. We used iterative categorization (directed content analysis followed by summative content analysis) to code and analyze the data both deductively (using SEIPS domains) and inductively (emerging themes).

Results

Factors affecting optimal urine ordering and collection included barriers at the person, process, and task levels. For ED nurses, barriers included patient factors, physician communication, reflex culture protocols, the electronic health record, urinary symptoms, and ED throughput. For ICU nurses, barriers included physician notification of urinalysis results, personal protective equipment, collection technique, patient body habitus, and Foley catheter issues.

Conclusions

We identified multiple potential process barriers to nurse adherence with evidence-based recommendations for ordering and collecting urine cultures in the ICU and ED. A systems approach to identifying barriers and facilitators can be useful to design interventions for improving urine ordering and collection practices.

Promoting appropriate urine culture management to improve health care outcomes and the accuracy of catheter-associated urinary tract infections

Published literature indicates that the unjustified ordering or improper collection of urine for urinalysis or culture from either catheterized patients or those without indwelling devices, or misinterpretation of positive results, often leads to adverse health care events, including increased financial burdens, overreporting of mandated catheter-associated urinary tract infection events, overtreatment of patients with antimicrobial agents, selection of multidrug-resistant organisms, and Clostridium difficile infection. Moreover, national guidelines that provide evidence-based direction on core processes that form the basis for subsequent clinical therapy decisions or surveillance interpretations; that is, the appropriate ordering and collection of urine for laboratory testing and the treatment of patients with symptomatic urinary tract infection, are not widely known or lack adherence. This article provides published evidence on the influence of inappropriate ordering of urine specimens and subsequent treatment of asymptomatic bacteriuria and associated adverse effects; reviews research on bacterial contamination and preservation; and delineates best practices in the collection, handling, and testing of urine specimens for culture or for biochemical analysis in both catheterized and noncatheterized patients. The goal is to provide infection preventionists (IPs) with a cohesive evidence-based framework that will assist them in facilitating the implementation of a urine culture management program that reduces patient harms, enhances the accuracy of catheter-associated urinary tract infection surveillance, improves antibiotic stewardship, and reduces costs.

Performance of the dipstick screening test as a predictor of negative urine culture

Objective

To investigate whether the urine dipstick screening test can be used to predict urine culture results.

Methods

A retrospective study conducted between January and December 2014 based on data from 8,587 patients with a medical order for urine dipstick test, urine sediment analysis and urine culture. Sensitivity, specificity, positive and negative predictive values were determined and ROC curve analysis was performed.

Results

The percentage of positive cultures was 17.5%. Nitrite had 28% sensitivity and 99% specificity, with positive and negative predictive values of 89% and 87%, respectively. Leukocyte esterase had 79% sensitivity and 84% specificity, with positive and negative predictive values of 51% and 95%, respectively. The combination of positive nitrite or positive leukocyte esterase tests had 85% sensitivity and 84% specificity, with positive and negative predictive values of 53% and 96%, respectively. Positive urinary sediment (more than ten leukocytes per microliter) had 92% sensitivity and 71% specificity, with positive and negative predictive values of 40% and 98%, respectively. The combination of nitrite positive test and positive urinary sediment had 82% sensitivity and 99% specificity, with positive and negative predictive values of 91% and 98%, respectively. The combination of nitrite or leukocyte esterase positive tests and positive urinary sediment had the highest sensitivity (94%) and specificity (84%), with positive and negative predictive values of 58% and 99%, respectively. Based on ROC curve analysis, the best indicator of positive urine culture was the combination of positives leukocyte esterase or nitrite tests and positive urinary sediment, followed by positives leukocyte and nitrite tests, positive urinary sediment alone, positive leukocyte esterase test alone, positive nitrite test alone and finally association of positives nitrite and urinary sediment (AUC: 0.845, 0.844, 0.817, 0.814, 0.635 and 0.626, respectively).

Conclusion

A negative urine culture can be predicted by negative dipstick test results. Therefore, this test may be a reliable predictor of negative urine culture.

Antimicrobial Stewardship Approaches in the Intensive Care Unit

Antimicrobial stewardship programs aim to monitor, improve, and measure responsible antibiotic use. The intensive care unit (ICU), with its critically ill patients and prevalence of multiple drug-resistant pathogens, presents unique challenges. This article reviews approaches to stewardship with application to the ICU, including the value of diagnostics, principles of empirical and definitive therapy, and measures of effectiveness. There is good evidence that antimicrobial stewardship results in more appropriate antimicrobial use, shorter therapy durations, and lower resistance rates. Data demonstrating hard clinical outcomes, such as adverse events and mortality, are more limited but encouraging; further studies are needed.

Performance of urinalysis tests and their ability in predicting results of urine cultures: a comparison between automated test strip analyser and flow cytometry in various subpopulations and types of samples

Aims

Results of urinalysis are available earlier than urine culture results. If urinalysis can predict results of culture, early decision can be made on treatment and whether urine samples should be cultured. This study sought to compare the performance of urinalysis tests by automated test strip analyser (nitrite and leucocyte esterase) with flow cytometry (bacteria and white cell count) in different subpopulations and types of samples.

Methods

Consecutive urine samples (n=2351) from a population with a median age of 45 years, 37.2% men, were tested. Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of the tests were calculated using contingency tables. The gold standard was positive urine culture with cut-off >105 CFU/mL.

Results

14% of the cultures were positive (95.6% monomicrobial, 74.7% Enterobacteriaceae). Overall, nitrite test was the most specific (98.7%) but the least sensitive (43.2%). Bacteria count was the most sensitive (91.7%) and highly specific (87.5%). In infants <24 months, the sensitivity of bacteria count was reduced (86.1%), but specificity was high (95.9%). The specificity of nitrite was reduced in urine from the in-and-out procedure (81.9%). The sensitivity of bacteria count was reduced in bag specimens urine (83.3%) and in urine from indwelling catheter (84.7%). All tests showed a high NPV. The NPV of the combined flow cytometry tests was higher than those of automated test strip analyser (99.1% vs 97.4%).

Conclusions

Overall, the performance of urinalysis is excellent. Flow cytometry tests performed better than automated test strip analyser in ruling out urine to be cultured.

Antimicrobial Stewardship: How the Microbiology Laboratory Can Right the Ship

Antimicrobial stewardship is a bundle of integrated interventions employed to optimize the use of antimicrobials in health care settings. While infectious-disease-trained physicians, with clinical pharmacists, are considered the main leaders of antimicrobial stewardship programs, clinical microbiologists can play a key role in these programs. This review is intended to provide a comprehensive discussion of the different components of antimicrobial stewardship in which microbiology laboratories and clinical microbiologists can make significant contributions, including cumulative antimicrobial susceptibility reports, enhanced culture and susceptibility reports, guidance in the preanalytic phase, rapid diagnostic test availability, provider education, and alert and surveillance systems. In reviewing this material, we emphasize how the rapid, and especially the recent, evolution of clinical microbiology has reinforced the importance of clinical microbiologists' collaboration with antimicrobial stewardship programs.